Edmab

The experimental adhesive system (EXP) was formulated as in previous study,^{14 (link)} using the following monomers (wt.%): HEMA (25%), 4-META (30%), TEGDMA (25%) (Essthec, Inc. Essington, PA, USA). Acetone (15%) and water (4%) were used as solvents and Camphorquinone (0.5%) and EDMAB (0.5%) (Ethyl 4-(dimethylamino)benzoate – Aldrich Chemical Company, Inc., Milwaukee, WI, USA) were incorporated as photosensitizer and reducing agents, respectively. The components of the adhesive were weighed using an analytical balance (AUW 220D, Shimadzu, Tokyo, Japan), mixed and homogenized in a dual centrifuge (150.1 FVZ SpeedMixer DAC, FlackTek Inc., Herrliberg, Germany) at 1300 rpm for 2 minutes.
The MMP inhibitor GM1489 (EMD Chemicals, Inc. San Diego, CA, USA) was incorporated in this formulation in different concentrations 0, 1 µM, 5 µM and 10 µM, obtaining four different experimental adhesives. The adhesive system Adper Single Bond 2 (SB) (3M ESPE, Sumaré, SP, Brazil) was used as a commercial reference and also received different concentration of GM1489. After incorporation of GM1489 in each adhesive system, they were homogenized at 2400 rpm for 2 min.^{14 (link)}Figure 1 shows the tested groups.
Figure 1

A model adhesive blend was formulated using the monomers HEMA, BISGMA, UDMA, and GDMA (Esstech Inc., Essington, PA, USA). Ethanol and water were used as solvents and Camphorquinone and EDMAB (ethyl N,N-dimethyl-4aminobenzoato) (Aldrich Chemical Company, Inc., Milwaukee, WI, USA) were incorporated as a photosensitizer and a reducing agent (Table 1). These chemicals were weighed in an analytical balance (AUW 220D, Shimadzu, Tokyo, Japan), then mixed, and homogenized in a dual centrifuge (150.1 FVZ SpeedMixer DAC, FlackTek, Inc., Hamm, Germany) at 2400 rpm for 2 min. Afterwards, ZnCl₂ was added in concentrations (wt.%) of 0%, 2.0%, 3.5%, and 5.0% (Sigma-Aldrich, St. Louis, MO. #1208465) to the model adhesive, obtaining four different experimental adhesives (Zn0, Zn2, Zn3.5, Zn5, and SB). The adhesive system Adper Single Bond 2 (SB) was used as a commercial reference. The compositions of all adhesive systems are shown in Table 1.
All adhesives were light cured using a quartz-tungsten-halogen unit (Optilux 501 Demetron Inc., Danbury, CT, USA), at an irradiance of 650 mW/cm², which was monitored using a radiometer (model 100, Demetron Inc., Danbury, CT, USA). This study followed the methods of da Silva et al., 2015 [17 (link)].